In the past, designers of military communication systems have endeavored to enhance security in communication equipment used with classified information. TEMPEST is a U.S. Department of Defense (DOD) program to develop methods of preventing the compromise of government and military information by reducing or eliminating unintended electronic emissions. One approach used in the past to reduce unintended electronic emissions has been to use a constant current shunt voltage regulator to prevent emission of signals on the power lines of communication equipment. While these current shunt regulating power supplies have many advantages, they also have significant drawbacks. "Red" information is used herein to denote information which is classified by the DOD as secret and, therefore, not to be permitted to be communicated to persons other than those having a predetermined clearance to receive such red information. "Black" information is used to denote information which is not classified by the DOD as secret.
Typically, this type of voltage regulator provides a clean source of voltage, but it does it by drawing a constant amount of power from the primary voltage source, irrespective of the immediate power needs. Furthermore, this power level is set so that it exceeds the maximum demanded power level. During normal, non-peak power levels, and during non-classified or non-"red" operations, these prior art shunt regulators dissipate large amounts of unnecessary power in the form of undesirable heat.
Consequently, there exists a need for improved methods and systems for regulating power supplies which have reduced power dissipation and which concomitantly provide for isolation of power transients and their associated undesirable emissions.